Comparative evaluation of the combined application of titanium implants and calcium phosphate bone substitutes in a rabbit model

Abstract Objectives To study the healing of defects around titanium implants filled with biphasic calcium phosphates ( BCP ). Material and methods Forty custom‐made, titanium implants (Ti) with a diameter of 5 mm, and length of 8 mm, with two‐sided gaps, were fabricated and installed in the femoral condyle of 20 rabbits. Following a randomization protocol, implants were alternately installed in one condyle without BCP bone substitute material (Ti) in the gaps and in the contralateral condyle gaps were filled with BCP bone substitute material (Ti+ BCP ). The implants were retrieved after 4 and 12 weeks of healing, after which histological and histomorphometrical analyses were done to assess the percentage of bone implant contact ( BIC ), the percentage of bone area ( BA ) and the percentage of particle area ( PA ) within the region of interest ( ROI ); the rectangular area joining the two arms of the L ‐shaped implant was considered as the ROI . Results After 4 and 12 weeks of healing, Ti+ BCP showed significantly higher BIC and BA values compared to Ti. Further, the BCP particles showed a significant decrease from 4 to 12 weeks of healing. The BCP particles ( PA ) showed a significant reduction from 31.6 ± 11.0% at 4 weeks to 21.0 ± 7.2% at 12 weeks. Conclusion The addition of BCP bone substitute to fill peri‐implant gaps significantly enhanced both bone formation (~2.5‐fold) and bone to implant contact (>2‐fold) for the custom‐made titanium implants with two‐sided gaps.